Field of Invention
This invention relates to a display panel and, in particular, to a display panel with a better display quality.
Related Art
With the progress of technologies, flat display devices have been widely applied to various kinds of fields. Because liquid crystal display (LCD) devices have advantages such as compact structure, low power consumption, less weight and less radiation, they gradually take the place of cathode ray tube (CRT) display devices, and are applied to various electronic products, such as mobile phones, portable multimedia devices, notebooks, LCD TVs and LCD screens.
A conventional LCD device mainly includes an LCD panel and a backlight module which are disposed opposite to each other. The LCD panel mainly includes a color filter (CF) substrate, a thin film transistor (TFT) substrate and a liquid crystal layer disposed between the two substrates. The CF substrate, the TFT substrate and the LC layer can form a plurality of pixel disposed in an array. The backlight module emits the light passing through the LCD panel, and the pixels of the LCD panel can display colors to form images accordingly.
Regarding the wide viewing angle technology for the VA LCD (Vertical Alignment LCD) panel, the manufacturer of the display device has utilized the photo-alignment technology to control the alignment direction of the LC molecules, so as to enhance the optical performance and the yield of the LCD panel. The photo-alignment technology form the multi-domain alignment in each pixels of the panel, so that the LC molecules in the pixel can be oriented towards, for example, four different directions. However, although the VA LCD panel made by the photo-alignment technology has better characteristics of high contrast ratio (CR) and short response time (RT), the side view effect thereof is worse than that of the FFS (fringe field switching) LCD panel or the IPS (in-plane switching) LCD panel.
Refer to FIG. 1A, which is a schematic diagram showing the gamma (γ) curves corresponding to the different gray levels displayed by a conventional VA LCD panel. Herein, the four-domain alignment is illustrated as an example. The curves C1, C2, C3 in FIG. 1A represent the gamma curves with respect to the front view, the side view of 45° and the side view of 60°, respectively. From FIG. 1A, it can be found that the side view will undergo a serious washout problem when the VA LCD panel is formed by the four-domain alignment, and that is, the image will become whiter because the it is too bright at the side view. Therefore, the display quality at the side view is inferior.
Moreover, refer to FIG. 1B, which is another schematic diagram showing the gamma curves corresponding to the different gray levels displayed by another conventional VA LCD panel. Herein, the pixel is divided into two areas (such as an area A and an area B) and the eight-domain alignment is illustrated as an example. The compensation which results from different voltage-transmittance curves for the areas A and B at the front view and side view helps the low color shift (LCS). The curves C4, C5(A), C6(B) in FIG. 1B are respectively the curve with respect to the front view, the gamma curve with respect to the area A and the gamma curve with respect to the area B, and the curve (C5+C6) is the sum of the gamma curves with respect to the area A and the area B. In comparison with FIG. IA, although the washout problem occurring in the VA display panel can be improved by the LCS technology shown in FIG. 1B, its display quality at the side view still can't as fine as the FFS display panel or IPS display panel.
Therefore, a display panel which can have a better side view effect with a better display quality is needed.